Cao Jiangnan, Cheng Yongqiang, Tang Ning
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China.
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China.
Food Res Int. 2025 Nov;220:117131. doi: 10.1016/j.foodres.2025.117131. Epub 2025 Jul 28.
This study systematically investigates the influence of calcium concentration on the structural, rheological, mechanical, and drug release properties of L-phenylalanine (L-Phe) hydrogels prepared from supersaturated L-Phe solutions, without the need for chemical modification. Rheological analyses revealed strain-dependent behavior and robust gel formation, with elasticity decreasing as calcium concentration increased. Mechanical testing showed a non-monotonic relationship between calcium concentration and both hardness and viscosity, peaking at 0.1 M. Microstructural analysis using scanning electron microscope and confocal microscopy demonstrated significant morphological transitions, from linear fibers to entangled structures and aggregated bands, with increasing calcium levels. X-ray diffraction and small-angle X-ray scattering (SAXS) analyses confirmed a shift from ordered crystalline to amorphous structures. SAXS further indicated changes in aggregate size, distribution, and fractal dimensions. Fourier transform infrared spectroscopy revealed enhanced interactions between calcium ions and L-Phe molecules, including hydrogen bonding and coordination. In vitro drug release studies, employing riboflavin as a model drug, demonstrated enzyme-mediated release in simulated intestinal fluid (SIF), with release rates modulated by calcium concentration. Molecular dynamics simulations provided atomic-level insights into the gelation process, highlighting the formation of compact and stable structures mediated by Phe‑calcium interactions and the generation of cavities within the gels. Collectively, these findings underscore the critical role of calcium concentration in tuning the properties of L-Phe hydrogels, offering valuable guidelines for designing these materials for diverse biomedical applications.
本研究系统地研究了钙浓度对由过饱和L-苯丙氨酸（L-Phe）溶液制备的L-苯丙氨酸水凝胶的结构、流变学、力学和药物释放性能的影响，无需进行化学修饰。流变学分析揭示了应变依赖性行为和稳健的凝胶形成，随着钙浓度的增加弹性降低。力学测试表明钙浓度与硬度和粘度之间存在非单调关系，在0.1 M时达到峰值。使用扫描电子显微镜和共聚焦显微镜进行的微观结构分析表明，随着钙含量的增加，形态发生了显著转变，从线性纤维到缠结结构和聚集带。X射线衍射和小角X射线散射（SAXS）分析证实了从有序晶体结构到无定形结构的转变。SAXS进一步表明聚集体尺寸、分布和分形维数的变化。傅里叶变换红外光谱揭示了钙离子与L-Phe分子之间增强的相互作用，包括氢键和配位作用。体外药物释放研究以核黄素作为模型药物，证明了在模拟肠液（SIF）中的酶介导释放，释放速率受钙浓度调节。分子动力学模拟为凝胶化过程提供了原子水平的见解，突出了由苯丙氨酸-钙相互作用介导的致密稳定结构的形成以及凝胶内空洞的产生。总的来说，这些发现强调了钙浓度在调节L-Phe水凝胶性能方面的关键作用，为设计用于各种生物医学应用的这些材料提供了有价值的指导。
